A projection type image display apparatus of a liquid crystal projector for example is required to achieve both of a higher output of a light source lamp and a minimization. Thus, a luminous tube in a reflector of a light source lamp uses a high-pressure mercury lamp or a metal halide lamp for example that emits light with a high intensity at a high temperature. However, a part of the light source lamp having the highest temperature is heated to a temperature of about 1000° C. and thus the light source lamp is cooled by air blown from a fan. This light source lamp exhausts air of a high temperature that is higher than that of a power source unit. Thus, the high temperature is solved by maximizing the capability of the exhaust fan (rotating speed), by increasing the size of the exhaust fan, or by providing a plurality of exhaust fans.
Japanese Patent Laid-Open Publication No. H09-90511 (Patent Publication 1) discloses a projection type image display apparatus having a fan for cooling a light source lamp in which a part of a duct extending from this fan to a light source lamp that is opposed to the light source lamp includes an opening (air blow outlet). Japanese Patent Laid-Open Publication No. 2000-19644 (Patent Publication 2) discloses a projection type image display apparatus structured so that two exhaust fans are provided in parallel to each other in the vicinity of a light source lamp to discharge exhaust air from the light source lamp or a power source unit for example.
However, in the above conventional light source lamp cooling mechanism as disclosed in Patent Publication 1, the fan and the air blow outlet are arranged in consideration of only the cooling of the light source lamp. Thus, when this structure cools the light source lamp, this structure causes a proportional increase in the temperature of the exhaust air. An excessively-high exhaust air temperature causes an increased number of complaints from users. Furthermore, the structure of Patent Publication 2 requires an increased interval between a side wall of a housing and the exhaust fans arranged to be parallel to each other, thus hindering the structure from being minimized. For reducing the temperature of the exhaust air, a structure may be considered in which exhaust air of a high temperature from the light source lamp and exhaust air of a low temperature from the power source unit for example can be mixed by inclining the respective exhaust fans arranged to be parallel to each other to form an inverted V-like shape in the exhaust directions thereof. However, this structure also requires a space and thus is hindered from being minimized.
In the conventional technique as described above, the cooling of the light source lamp having a high output causes an increased temperature of an exhaust air, which exceeds a permissible range of users, thus making it difficult to achieve both of the cooling of the light source lamp and the reduction of the exhaust air temperature. When the difficulty is tried to be solved by increasing the output of the fan or by increasing the number of fans, a disadvantage is caused in which noise is increased or the apparatus is prevented from being minimized.